Flame cutting machines



June 14, 1960 Original Filed Aug. 23, 1955 H. l. sJbsTEuT FLAME CUTTING MACHINES 3 Sheets-Sheet 1 June 14, 1960 H 1. SJOSTEDT 2,940,748

FLAME CUTTING MACHINES Original Filed Aug. 23, 1955 3 Sheets-Sheet 2 June 14, 1960 H. l. SJGSTEDT 8 FLAME CUTTING MACHINES Original Filed Aug. 23, 1955 3 Sheets-Sheet 3 lb -I FLAME CUTTING MACHINES Helge Ingvar Sjiistedt, Kilian Zollsgatan 29b,

0, Sweden Continuation of application Ser. No. 530,142, Aug. 23, 1955. This application July 21, 1958, Ser. No. 749,766

Claims priority, application Sweden Aug. 28, 1954 9 Claims. (Cl. 266-23) This invention relates to a flame cutting machine of the type comprising a carriage supporting a blowpipe or similar tool and having a pair of coaxial travelling wheels to be driven and steered on a plane surface of a workpiece by an external force, the blowpipe or similar tool being disposed at one side of the carriage outside the wheels on said carriage side, and is a continuation of my copending application Serial No. 530,142 filed August 23, 1955, now abandoned.

The principal object of the invention is to provide a fiame cutting machine of this type having means capable of holding the linear speed of the blowpipe or similar tool constant also on cutting irregularshapes including sharp bends to one or the other side, thus producing even and clean-cut edges so that a further treatment can be dispensed with.

With reference thereto a more specific object of the invention is to provide a flame cutting machine of the above type having a rotary speed governor and a sun-andplanet gear connected between the wheels and the governor at such transmission ratios between the wheels and the speed governor, selected in correspondence with the distances between the wheels and the blowpipe, that the speed equalization produced by the sun-and-planet gear relates to the laterally disposed blowpipe whereby the linear speed of said blowpipe is always proportional to the r.p.m. of the speed governor.

Further objects and advantages of the invention will become apparent from the following description, reference being had to the accompanying diagrammatic drawings in which:

Figure 1 is a cross section on line 1-1 in Figure 2;

Figure 2 is a side view as seen from the left in Figure 1 Figure 3 is a cross section through an embodiment in which the sun-and-planet gear is connected in another way than in Figure 1 and is supplemented by additional s g Figure 4 is a cross section through an embodiment including a sun-and-planet gear of another design; and

Figure 5 is a section through the sun-and-planet gear on line V--V in Figure 4.

In all embodiments illustrated, the machine comprises a body 1 carried by a pair of coaxial wheels 2, 3 which are mounted on said body. An arm 1b laterally projects from the body 1 and carries at its outer end a blowpipe 4 which is directed towards a point on the prolongation of the straight line between the points of support of wheels 2, 3 on a plane base, as is shown in Figures 1 and 2. The said point defines the position of the blowpipe to the extent required in the present connection. Furthermore, the machine body 1 contains in all embodiments a speed governor 5 and a sun-and-planet gear designated 6, 7 and 8 as shown in Figures 1, 3 and 4 respectively, in the drawings and interposed between the wheels 2, 3 and the speed governor 5. The machine also has a downwardly bent grip 1a which projects from the body 1 nited States Patent 2 ,940,748 Patented June 14, 1960 offer so large a resistance to a change or increase in its speed that the external force necessary for steering and possibly driving the machine at correct speed cannot ap-- preciably affect the speed or increase it. The wheels are knurled or otherwise designed to prevent slipping.

In Figures 1 and 3 the sun-and-planet gear is of the type ordinarily used as a difierential gear in automobiles, and in Figures 5 and 6 it is of another type having spur gears. The sun-and-planet gear may possibly consist of a ball or roller bearing, the balls or rollers of which form the planet gears in a planet (ball) cage.

The sun-and-planet gear is not connected in the ordinary way, like the diiferential gear of an automobile, but adapted to hold the speed of the laterally disposed blowpipe constant, which implies thatits equalizing effect, controlled by the governor, is distributed on the two wheels with due regard to their different distances from the blowpipe. As a result thereof, the speed of the carriage proper can vary considerably and also its direction of movement may temporarily be reversed on cutting sharp curves or corners when the carriage is rapidly swung, eg. through or more, with the blowpipe as the center by the action of an external steering force while the blowpipe continues to move uninterruptedly in the operating direction at the speed defined by the speed governor.

As will appear from Figure l, in the embodiment shown therein the distance of the blowpipe 4 from the adjacent wheel 2 is equal to the relative distance of the wheels, and the sun-and-planet gear comprises in a known manner two sun wheels 9, 10 which are coaxial to the travelling wheels 2, 3 and are of the same diameter, a planet cage 11 and a plurality of planet gears 12 mounted thereon. The sun Wheel 9 on the blowpipe side is freely mounted on the axle of the travelling wheel 2 and provided with a gear rim 13 meshing with a gear 14 on the shaft of the speed governor 5. In normal operation the sun gear 9 thus has a constant r.p.m. which is applied to it by the speed governor or by the speed governor and an external driving force in combination. -The other sun wheel 10 is fixedly mounted on the axle of the travelling wheel 3, and the planet cage 11 is fixedly united with the axle of the travelling wheel 2.

it is assumed that the machine operates under rectilinear movement, steered by an external force, in such a direction that the blowpipe is located on the left side as seen in the operating direction, the travelling wheels having the same speed under the control of the speed governor. If the blowpipe is to change direction to the left about a sharp corner, the machine is simply swung in the new direction by manual force exerted on the grip 1a at right angles to the operation direction. As a result, the speed of the two travelling wheels is increased, and thanks to the speed governor and the special manner in which the sun-and-planet gear is connected between said governor and the travelling wheels, the speed of the outer wheel 3 is increased twice as much as that of the inner Wheel 2, while the governor maintains the same r.p.m. and the blowpipe continues its forward travel. However, the change of direction can, be performed very rapidly, if the machine is small and light, and the are described by the blowpipe can thus be given so small a radius that it is not perceptible. The machine body proper is thus swung practically with the blowpipe as the center.

If the machine is to be swung to the right from the same normal position, the swinging movement is carried out accordingly. The direction of rotation of the two travelling wheels is now reversed, i.e. their speeds will be negative, and by the action of the speed governor the: sun-and-planett gear distributes the change of speed in' such away that for the outer wheel '3 itwill be twice as 'large as that of the inner wheel 2,"and the swinging movement isiperformed, if carried outrapidly, with the ,blowpipe as the center, while thet speed governorif it is also the drive motor' continuously drives the blowpipe at a constant speed andotherwise gives the required reaction tin relation to the sun-and-planet gear, by it inertia. f I s 7 By swinging the machine more or less rapidly, without any interruption of the drive power, by exerting a lateral 7/ forcepn thegrip '1a, it is possible to cause the blowpipe to follow any curves whatever at a'constant speed which is determined by the speed governor.

' j The explanation of these performances lies in the relations of distances and transmission ratios, that will appear,

from Figure ,1. The two suni'wheels 9 and 10 being e' qually,large the transmission ratio of the inner wheel'z,

i;e.'lthe,wheel adjacent the blowpipe, and the sun wheel 9i w hich' by reason of gearing 13, 14 represents the'speed. governor; thus will obviously be 1:2, provided that the outer wheel 3jiS'lQCkCd, .Whl1C the transmission ratio of theputer wheel;3 and the sun wheel 9; provided that the innerzwheelzis locked, will be 1:1 the direction of ro- 1 tationfheing reversed. This corresponds numericallyi -to j theizdistance' that the respective wheel isispacedapart from'thebloyvpipe, and if the transmission ratios of, the wheels in; relation to the speed governor are designated Rs and Rg, jrespeotiyelypand 'their distances from the 'Q' blowpipe- .are de signated a and 41 respectively, the relation can be expre ssed by the formula V the min'ps indicating that the direction of rotation is'treverscdsfor one'wheel, It' should perhaps tbe pointed out that thisformula relates to the construction proper,

. and as regards function this formula is valid only in the, above-mentionedspecial case that one wheel 2 or'3 is 7 '*locked and themachine'thus circles, the point of'support closer to the inner wheel but in a simple distance relation'to the wheels inasmuch as its distance to the inner wheel is one fourth of its distance to'the outer wheel. Accordingly, the diameter of the inner sun wheel 41 of the sun-and-planet gear is one third of the diameter of its, outer sun wheel"44, -'a'i1d this transmission ratio of the outer wheel-tothe outer sun wheelA l-representing the speed governor is thus rrii'n'u's 3":1;.tlie' inner wheel 2 being locked, while the, transmission" ratio .of thefl-inner wheel 2 to the sun wheel" 44 is 324, the outer wheel 3 beingjlocked. The relation of the two transmission ratios. is thus' numerically the same as between the distances of the wheels 2, s w the blowpipe, vizI 1E4, though of the opposed sign. a a j s The laterally disposedblowpipei4 'need not bearranged exactly on-the' prolongation of the wheel axis. For, on cutting sharp curves, the steering of the machinemay be facilitated if the blowpipe is displaced somewhat forwards from i this line. It is true' that an more the blowpipegspeed isintroduced by this arrangement, but as a rule ;this error is of no importance: Such'a displacement of the'blowpipe'is'also advantageous, for beginriingajcut to be made at right angles ,to the edge of a metal sheet orfor finishing-such a cut, a

The cutting machine can 'be made so compact and of so low a weight'that itmay conveniently be carried" with onehand. To facilitate rapidtransportiit may have a release mechanism for disconnecting the speed governor, or an additional pair of t wheelswhich normally depend freely but on which the machine can betplaced so that the :ordinary travelling wheels ara liftedoff the base.

' jiThe cuttingmachin'e is'otherwise eciuipped with such prior art details as are usually tobe'foundin'machines of travelling wheel'sd that it forms the center of rotation;

Ifthe distance of the blowp'ipe -from thej travelling wheels has thento' be changed, this change can be compensated forbyan adjustment 'of the ripm'. or thefspeed governorr or the wheel serving asthe center, or in the case that 7 die speed governor is locked, i.e;has'an r.p.1n'. or" 0, it

'Figure' 3 shows another arrangement of the sun-andplanet gear fbetween the speed governor and the wheels. The said gear is of the same type as in Figure 1, but in 'Figurel'3 itis theplanet.cagezl that is provided with agear rim 22 meshing with a gear 23 on the shaft of, "the, governorand owing to the location of the blowpipe the twosun wheels 24 25 are, connected to the a respective travelling wheel '2, "3 by means ot different gear" 7 being then only'possible to. let the machine make 'a'circu lar movement with the blowpipe serving as the center, i t

this type, such asgas hoses and valves, electric lines with switches-forthe speed go'vernor, if: it is an electric'motor,

and means. for adjusting the rpm. and direction of rotation of-the speedgovernorw r fIn rectilinear cutting the machine may of course be steered by means of a ruler or by a, direct fixed intercom .nection of the two travellingwheels', and in circular cutting it may be arranged as a beamtrammel ,It can "also cut disks within certain diameterlimitsbylocking one The invention may be em bodied'in other specific forms without departing from the spirit or essential' character istics thereof. ',The present embodiments are therefore to V be considered in =111-respectsas illustrative and'not restrictive, the scope of the invention being indicated by; f the appended claims rather than by the foregoing clescrip tion, and-all changeswhich come the meaning and trains 26,527, 28 and 29, 30, 31, 3;; respectively. The 7 gear train'of the outer wheel 3 contains one gear more than that of the inner wheel 2, and "as compared with the latter gear train it gives half as, large a transmission 'ratio between the wheel and the speed governor, correspending to the fact that thedis tance between th'e blow: a

pipe 4 and the outer wheel 3 is twice as large as'that between the blowpipe and the inner wheel 2.

Figu'e 4, nd 5 'show'a 'sun-and-planet gear 8 having only 'spurgears. It'has an inner sun wheel 41 which is se ured to .the axle oi the outer wheel 3;and meshes witlraplurality. ofplanet gears'42 which are mounted in a planet cage 43 *s'ecured'tothe axle of theinnerwheel 2 andmesh with anouter sun whee1 44 mounted for tree rotation in the machine body'and having an external 7 gear meshing with a gear 45 on thershaft of the speed governor. v 1 a a V l V V --In this embodiment the' blowpipe has been disposed range of equivalency of the claims are therefore intended 55 7 to beembraced therein;

What is claimedtand desired to be secured by United StatsLetters Pafent'i'si V 1. A- flame'cutting'machinefcomprising: a' carriagei a pair of coaxial travelling wheelsrotatably mounted on V saidtcarriageg a supportimember on said carriage pro viding, ith'said'wheiels; atfleast a three point support for engagement with a plane snrface of a workpiece; a

blowpipemeans s'ecured o'n said carriage, disposed a spaced distance to one side of said pairof whcelsand e5 .r of, thestraight. line between'the 'points of support of said N 'wheelson the plane surface; a speed governed'power 7 supply means including-gear means carried by saidvcarr directed to. a'po sition,-substantiallyqon a prolongation r'iage and drive connected-with said wheels; 'said'igear means including a difierentialgdevice enabling, a speed governed drive through saidwheels to provide a constant governed progressive movement of: said blowpipe means along the workpiece and at the same time to enable forward, rverse'and relative' ro'tations 'of said pair iof Wheels, to guide the direction'of movement of said 'flaine cutting machine, solely by application of an external guiding force.

2. A work performing machine comprising: a carriage; a pair of coaxial travelling wheels rotatably mounted on said carriage; a support member on said carriage providing, with said wheels, at least a three point support for engagement with a plane surface of a workpiece; a work performing means secured on said carriage and disposed a spaced distance to one side of said pair of wheels with its work engaging portion substantially on a prolongation of the straight line between the points of support of said wheels on the plane surface; a speed governor carried by said carriage and gear means carried by said carriage and drive connected between said speed governor and said wheels to enable a constant governed progressive movement of said work performing means along the workpiece, said gear means including a differential device enabling forward, reverse and relative rotations of said pair of Wheels on guiding the direction of movement of said work performing means by application of an external guiding force.

3. A work performing machine as defined in claim 2 wherein said differential device includes two primary coaxial, relatively rotatable gear members and an epicyclic assembly-with a carrier member coaxial with and rotatably relative to said two primary gear members with planet gear means meshed with said two primary gear members; one of said members being drive connected to said speed governor and each of the remaining two of said members being drive connected to an associated one of said wheels; the gearing drive, in the absence of application of external guiding force on the movement of said machine, between said one member and the one wheel closest to said work performing means providing an opposite direction of rotation than the gearing drive between said one member and the other of said two wheels and a drive ratio to said one wheel having a relationship to the drive ratio to the other wheel which is directly proportional to the relationship between the distance of said one wheel from said work performing means and the distance of said other wheel from said work performing means.

4. A work performing machine as defined in claim 3 wherein said one member is one of said two primary gear members, the member connected to said one Wheel is said carrier member and the member connected to said other wheel is the other of said two primary gear members.

5. A work performing machine as defined in claim 3 wherein said one member is said carrier member, gear train connects one of said two primary gears to one of said wheels and a second gear train having one more gear than said first gear train connects the other of said two primary gears to the other of said Wheels.

6. A work performing machine as defined in claim 3 wherein said difierential device is a planetary type mcyclic gearing with a sun gear member, a ring gear member and a planetary assembly including a carrier member with at least one planet gear enmeshed with said sun gear member and said ring gear member; said ring gear member being said one member; said planet carrier member being the member connected to the wheel closest to said work performing means; and said sun gear member being the member connected to the other wheel.

7. A work performing machine as defined in claim 2, wherein said speed governor is a speed governed electric motor for moving said carriage.

8. A work performing machine as defined in claim 2, wherein said carriage is movable only by application of external force and said governor is a centrifugal governor for limiting the utilization of the external force by braking.

9. A machine adapted to carry to tool over a workpiece at constant speed along an optionally curved path comprising: a carriage having a pair of coaxial travelling wheels and adapted to support the tool at its one side outside the travelling wheel of that side and provided with a speed governor; a transmission connecting said governor to the one of said travelling wheels located on the tool side to control the speed thereof; said transmission containing a differential device; and means connecting the second of said travelling wheels to said difierential device to add the rotation applied to said second travelling wheel by the movement on the workpiece of said carriage steered by an external guiding force, to the rotation of said one speed governed travelling wheel under such transmission ratios that the speed of the .tool is always substantially proprotional to that of said governor.

References Cited in the file of this patent UNITED STATES PATENTS 874,852 Lorenz Dec. 24, 1907 2,183,605 Bucknam et a1. Dec. 19, 1939 2,586,907 Bernard Feb. 26, 1952 FOREIGN PATENTS 7,080 Great Britain May 1, 1884 

